This trees made for arch.visualization. They are middle-poly count trees, just perfect for animations. It have been made with saving as much polygons and details as possible.
The problem was video memory and saving as much as possible of it with GPU render engine. Main format is max 2012 with standard materials.
There is also many 3d flexible formats
Diffuse and alpha map included

Terrain scene render have been made just for better understanding of look and optimization. Mountains not included

Polygons counted from both young and old trees together.

- - - - - - - - - - - You Can make 3d models by yourself - - - - - - - - - - - -
- - - - - - - - - - - - - - - but spent time will cost dearer - - - - - - - - - - - - -